To prevent numerous road accidents resulting from the fact that the driver of a transport vehicle has no precise indication of a an instant of time when the traffic light signal is changed, use is now made of diverse visual methods of indicating vehicle drivers of the time at his/her disposal for passing a crossroad or a pedestrian crosswalk. Indication of the remainder time is effected in the heretofore-known methods with the use of additional indicating elements which can be viewed by the driver simultaneously with the main traffic light signals (i.e., green, red, and orange). Used as such elements are symbols, arrows, numbers (DE Patent A NN 4,210,996, 3,929,342), luminous dots located either in line or round a circle and adapted till successively go out in a direction towards the main indication signal light (FR Patent A N 2,691,566; CH Patent A N 678,668), additional signal lamps of any color arranged in diverse ways with respect to the main signal lights and are turned on one after another at regular intervals which are in fact fractions of a lighting period of a main signal lamp, that is, green or red (FR Patent A N 2,126,134), timers counting down time (in seconds) within which one or the other signal lamp will be on (GB Patent A N 2,248,136).
However, use of additional indication elements is in a majority of cases inconvenient for drivers, because they are to keep watch simultaneously on two or more light signals carrying diverse information. Additional signal lamps (especially when a plurality of such lamps are used) arranged at various places with respect to the main signal lamps both vertically and horizontally, are out of drivers' field of vision, especially those of motor cars which are spaced 10-15 m away from the traffic light.
The technical solution closest to the herein-proposed one is a method of indicating the remainder time till a change in the traffic light signal (U.S. Pat. No. 200,860, wherein a change in the effective signal light is preceded by the red or green lamp starting flashing at variable-length intervals between flashes to inform about a change in the traffic light signal that is to come.
When the effective traffic signal lamp flashes at a final stage more than twice, this might misinform vehicle drivers, because they cannot accurately determine the instant when the signal light is changed; however, any misinformation in traffic signalling might result in unpredictable emergency after-effects. When a driver approaches the crossroad while, e.g., a green light is flashing, he/she has no prior knowledge of how much time remains before a change of the green light for the orange one. Thus, the information boils down to the sole fact that a change in the signal light is next to come. This compels a driver either to increase the speed in order to pass the crossroad before the "go" (green) signal is changed for the "no go" signal, or conversely to reduce the speed. In any of said cases this results either in overspeed or in a traffic jam and a danger of emergency situation occurs.